Jaker

I thought that wire looked familiar. Is it silicone insulation RC car battery wire? Those are Deans connectors, right?

My engine is a much smaller one, so I'm going to build mine with only 16 cells (9.2 ah). Plus it's a race car, so I'm looking to shave weight any way I can.

Thanks very much for the nicely detailed write up, and the feedback.

ToothDoc

Update: So far, winter has come and gone and no problems and no charging issues. I have put it in and pretty much forgotten it at this point. We'll see what summer heat does to the battery next...

stick

This is great news! Is it your daily driver?

ToothDoc

Yes, it's my daily driver.

ToothDoc

So now it's summer and the engine bay get pretty hot and it still works fine... No issues yet...

cholmes1

With summer coming to an end here in IL (and across the US) I am curious how your battery setup is working? Also, I could not find any postings of the DIY you mentioned earlier in the thread

ToothDoc

The battery has been flawless so far. Not one issue. After I know for sure it works through another winter, I'll post a complete DIY. I don't want anybody's car not working and be blamed for it. LOL If you want to see it for yourself, I'm in Lake Zurich. PM me.

Battman

Hello all;
I would like to input my 5 cents into the lithium battery discussion.
Mine has been in operation for 18 months, not one single problem !
I made my own as well and would be willing to offer them to others,

megomaniac

bump.... hows that battery holding up? I want to make one for my is300, each pack of four cells has its own positive and negative wire? is this so it self balances better?

ToothDoc

LOL, old thread revival. Lasted 2.5 years until I took my IS-F to the dealership for a buff. The porter/car wash guys left my doors open until the batteries were completely drained. Unfortunately, for Lithium Ion batteries, you don't want to drain them to 0 volts. 2 out of the 5 packs died - it still was recharging and working but they became completely out of balance.

I have a new version in the works that's even easier and cheaper and no soldering is required and balance is already going to be built in but still haven't figure out the low voltage shutoff issue. After I make that new version, you can be sure every car of mine from this point on will have my LiFePO4 packs! Stay tuned...

megomaniac

http://www.prioritystart.com/12vpromax.php
something like this could work I think, but it doesn't cut off the battery till 11.7v, is that too late? dropping from where they should be up at 13.2v or so?

or this
http://www.batterybrain.co.uk/productspage.php

ToothDoc

Hey, thanks for the link! I'm going to order the prioritystart and add that to my next battery!

megomaniac

to bad its another 1.5lbs! http://www.prioritystart.com/specs.php
I was thinking of building a battery with 24cells, 6 groups of 4.
best price I can find on ebay for a123 26650 is 4 at 32.99 free shipping (8.25/cell)
so it would cost $198 , 3.7lbs of cell , 13.8ah.

I found this link: http://www.emissions-free.com/catalog/i8.html
$6/cell so $144 before shipping, haven't tried contacting yet though....

or there's a nice looking shorai battery for $314.96 free shipping (lfx36 4.96lbs)
https://www.motomummy.com/store/prod...d=18829&page=1
and balance with
https://www.motomummy.com/store/prod...e-prnr-reviews

another source for a123 26650
(attn: newer mfg date batteries may be samsung 1100mah cells)
dewalt dc9280 8 cells
dewalt 9360 10 cells

ToothDoc

I'm actually going to "square" shaped cells in mylar instead of cylindrical cells. They're under the "green life" cells at maxamps.com You can get 90C 4.5 amps at 13.2 volts and double it up for up to 800 amps continuous or even get the 40C x 2 at 10.0 amphours. Double the capacity, but double the weight at same power levels (so it might handle a porter leaving the door open). 450 - 600 bucks for those cells.

If you are going to use it strictly for racing purposes, I think you can get away with 3 or 4 parallel sets of A123. My 5.0 V8 pulled about 500 amps during peak starting current... I figure you'll only pull 300-400 amps.

megomaniac

have you seen the headway lifepo4 cells on ebay?
they come in 10ah 15ah and 16ah.
they are relatively cheap, cause you don't need as many, could make a 16ah with just 4 cells.

edit: never mind, to achieve the required peak amp, the cost and weight is to much.....

these are neat, could do a 12cell 24ah 8.7lbs $285 before shipping.
http://stores.headway-headquarters.c...gory=BATTERIES